Fungicidal 3-(N-acyl-N-arylamino) lactones and lactams

ABSTRACT

3-(N-acyl-N-arylamino)-gamma-lactones, delta-lactones, gamma-lactams and delta-lactams have fungicidal activity.

RELATED APPLICATIONS

This application is a continuation-in-part of application Ser. No. 631,351, filed Nov. 12, 1975, now U.S. Pat. No. 4,012,519, which in turn is a continuation-in-part of application Ser. No. 548,660, filed Feb. 10, 1975, now U.S. Pat. No. 3,933,860, the disclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

The invention is directed to fungicidal compounds which are particularly useful for the control of downy mildew fungal diseases, especially downy mildew disease of grapevines. Grape downy mildew has been a major economic disease since 1880. However, no entirely satisfactory fungicide has been developed for its control to date. For example, most commercial fungicides such as copper-containing fungicides (e.g., Bordeaux mixture) sulfenimide fungicides (e.g., Captan and Captafol) and thiocarbamate fungicides (e.g., Maneb) are generally effective only for preventing the growth of downy mildew. Grapevines which are already infected with downy mildew are not cured by the use of such fungicides. Also, many commercial fungicides used for downy mildew control, such as the sulfenimides, cannot be used on wine grapes shortly prior to the harvesting of the wine grapes because the fungicide inhibits the fermentation of the grapes.

SUMMARY OF THE INVENTION

It has now been found that 3-(N-acyl-N-arylamino) lactones and lactams are effective for the control of fungi, especially for downy mildew fungi. The compounds of the invention are effective both as protectant fungicides, i.e., they prevent or protect against fungal infections, and as eradicant fungicides, i.e., they eliminate and cure established infections. The compounds of the invention are especially preferred for the control of grape downy mildew because they do not inhibit the fermentation of grapes harvested from grapevines treated with the compounds of the invention. Also, the compounds of the present invention have been discovered to have surprisingly high effectiveness and eradicating grapevine downy mildew.

DESCRIPTION OF THE INVENTION

The 3-(N-acyl-N-arylamino) lactones and lactams of the invention are represented by the formula (I): ##STR1##

wherein Ar is phenyl or phenyl substituted with 1 to 3 of the same or different substituents selected from trifluoromethyl, trichloromethyl, fluoro, chloro, bromo, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms or nitro; R is the same or different and is hydrogen or alkyl of 1 to 6 carbon atoms; R¹ is phenyl, phenyl substituted with 1 to 3 of the same or different substituents selected from trifluoromethyl, trichloromethyl, fluoro, chloro, bromo, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms or nitro, alkyl of 1 to 6 carbon atoms, halovinyl of 1 to 3 of the same or different halogens selected from fluoro, chloro or bromo, or haloalkyl of 1 to 3 carbon atoms and 1 to 5 of the same or different halogens selected from fluoro, chloro or bromo; R² is hydrogen or alkyl of 1 to 6 carbon atoms; R³ is hydrogen or alkyl of 1 to 6 carbon atoms; n is 1 or 2; and Y is oxygen or N--R⁴ wherein R⁴ is hydrogen, alkyl of 1 to 6 carbon atoms, alkenyl of 3 to 6 carbon atoms, phenyl, phenyl substituted with 1 to 3 of the same or different substituents selected from trifluoromethyl, trichloromethyl, fluoro, chloro, bromo, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms or nitro.

Representative alkyl groups which R, R¹, R², R³ and R⁴ may represent are methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, pentyl, isohexyl, etc.

Representative halovinyl groups which R¹ may represent are 2-chlorovinyl, 2,2-dibromovinyl, trichlorovinyl, etc.

Representative haloalkyl groups which R¹ may represent include fluoromethyl, chloromethyl, bromomethyl, dichloromethyl, tribromomethyl, 2-chloroethyl, 1,1,2,2-tetrachloroethyl, perbromoethyl, 3-chloropropyl, etc.

Representative substituted-phenyl groups which Ar, R¹ and R⁴ may represent are 2-trifluoromethylphenyl, 2-fluorophenyl, 2,4-dichlorophenyl, 3,5-dibromophenyl, 4-methylphenyl, 2,6-diethylphenyl, 4-methoxyphenyl, 4-nitrophenyl, 2,6-dimethyl-4-chlorophenyl, etc.

Representative N-R⁴ groups are amino; alkylamino such as methylamino, ethylamino, isopropylamino, n-hexylamino etc.; alkenylamino such as allylamino, 3-butenylamino, etc.; and arylamino such as phenylamino, 4-chlorophenylamino, 4-tolylamino, etc.

Preferably Ar is phenyl or phenyl substituted with 1 to 2 of the same or different substituents defined above. More preferably Ar is phenyl or phenyl substituted with 1 to 2 fluoro, chloro, bromo or alkyl of 1 to 4 carbon atoms. Most preferably Ar is 2,6-dialkylphenyl.

Preferably R¹ is alkyl or 1 to 6 carbon atoms, phenyl, phenyl substituted with 1 to 2 of the same or different substituents selected from fluoro, chloro, bromo or alkyl of 1 to 4 carbon atoms, or haloalkyl of 1 to 3 carbon atoms and 1 to 2 chloro or bromo. More preferably R¹ is haloalkyl of 1 to 3 carbon atoms and 1 to 2 chloro or bromo. Most preferably R¹ is chloromethyl or bromomethyl.

Preferably R, R² and R³ are hydrogen.

Preferably R⁴ is hydrogen, alkyl of 1 to 6 carbon atoms, alkenyl of 3 to 6 carbon atoms, phenyl or phenyl substituted with 1 to 2 fluoro, chloro, bromo or alkyl of 1 to 4 carbon atoms.

Preferably Y is oxygen or alkylamino (N-R⁴ wherein R⁴ is alkyl). Most preferably Y is oxygen.

Preferably n is 1.

A preferred class of compounds is that represented by the formula (IA) ##STR2## wherein R¹ is halomethyl of 1 to 3 chloro or bromo atoms, R² is hydrogen or alkyl of 1 to 3 carbon atoms, R⁵ is hydrogen or alkyl of 1 to 3 carbon atoms and R⁶ is alkyl of 1 to 3 carbon atoms. The most preferred class of compounds represented by formula (IA) is that wherein R¹ is chloromethyl, R² is hydrogen and R⁵ and R⁶ are methyl or ethyl.

The compounds of formula (IA) are preferred largely because of their surprisingly high activity for eradicating and curing established fungal infections, particularly for downy mildew infection of grapevines and late blight infection of tomatoes.

Representative compounds of formula (I) include:

3-(N-acetyl-N-phenylamino)-gamma-butyrolactone

3-(N-propionyl-N-4-chlorophenylamino)-gamma-butyrolactone

3-(N-hexanoyl-N-4-methoxyphenylamino)-gamma-butyrolactone

3-(N-fluoroacetyl-N-2,6-dimethylphenylamino)-gamma-butyrolactone

3-(N-dichloroacetyl-N-2,6-diethylphenylamino)-gamma-butyrolactone

3-(N-3-chloropropionyl-N-3,4-dibromophenylamino)-gamma-butyrolactone

3-(N-benzoyl-N-4-nitrophenylamino)-4-methyl-gamma-butyrolactone

3-(N-4-chlorobenzoyl-N-2-methoxyphenylamino)-gamma-butyrolactone

3-(N-4-methylbenzoyl-N-3,4-dichlorophenylamino)-4,4-dimethyl-gamma-butyrolactone

3-(N-2,4-dimethylbenzoyl-N-2-fluorophenylamino)-gamma-butyrolactone

3-(N-4-methoxybenzoyl-N-4-methoxyphenylamino)-gamma-butyrolactone

3-(N-propionyl-N-2,6-dimethylphenylamino)-5-methyl-gamma-butyrolactone

3-(N-benzoyl-N-2,6-diethylphenylamino)-5-ethyl-gamma-butyrolactone

3-(N-chloroacetyl-N-3,4-dichlorophenylamino)-5-hexyl-gamma-butyrolactone

3-(N-chloroacetyl-N-2,6-dimethylphenylamino)-delta-valerolactone

3-(N-4-bromobenzoyl-N-3-methylphenylamino)-delta-valerolactone

3-(N-acetyl-N-2-propylphenylamino)-delta-valerolactone

3-(N-bromoacetyl-N-2,6-dimethylphenylamino)-6-methyl-delta-valerolactone

3-(N-pentanoyl-N-4-nitrophenylamino)-6-hexyl-delta-valerolactone

3-(N-2,4-dibromobenzoyl-N-4-methoxyphenylamino)-5-methyl-6-methyl-delta-valerolactone

3-(N-acetyl-N-2,6-dimethylphenylamino)-gamma-butyrolactam

3-(N-chloroacetyl-2,6-dimethoxyphenylamino)-gamma-butyrolactam

3-(N-benzoyl-N-2-nitrophenylamino)-gamma-butyrolactam

1-methyl-3-(N-chloroacetyl-N-2,6-dimethylphenylamino)-gamma-butyrolactam

1-allyl-3-(N-p-chlorobenzoyl-N-2,6-dimethylphenylamino)-5-phenyl-gamma-butyrolactam

3-(N-bromoacetyl-N-phenylamino)-1,5-dimethyl-gamma-butyrolactam

3-(N-chloroacetyl-N-2,6-dimethylphenylamino)-delta-valerolactam

3-(N-bromoacetyl-N-2,6-diethylphenylamino)-delta-valerolactam

1-methyl-3-(N-chloroacetyl-N-2,6-dimethylphenylamino)-delta-valerolactam and

1-ethyl-3-(N-bromoacetyl-N-2,6-diethylphenylamino)-6-methyl-delta-valerolactam.

The lactone compounds of the invention may be prepared by alkylating an aniline (II) with an alpha-halo-gamma-lactone or alpha-halo-delta-lactone (III) and subsequently acylating the alpha-(N-arylamino)-gamma-lactone or delta-lactone (IV) with an acyl halide (V) to give the 3-(N-acyl-N-arylamino)-gamma-lactone or delta-lactone product (I), as depicted by the following equations: ##STR3## wherein Ar, R, R¹, R², R³ and n have the same significance as previously defined, and X is chloro or bromo.

The alkylation reaction (1) is conducted in the presence of a base. Suitable bases are inorganic alkali metal carbonates such as sodium carbonate or potassium carbonate. Generally, substantially equimolar amounts of reactants (II) and (III) and the base are employed. In one modification of the reaction, a molar excess of the aniline reactant (II) is used as the base, and no additional base is employed. The reaction is conducted in inert polar organic solvents, e.g., apolar diprotic solvents such as dimethylformamide and acetonitrile, at reaction temperatures varying from 25° C to 150° C, preferably from 50° C to 150° C. The reaction pressure may be atmospheric, subatmospheric or superatmospheric. However, for convenience of conducting the reaction, the pressure is generally atmospheric. The reaction time will, of course, vary depending upon the reactants and the reaction temperature. Generally the reaction time is from 0.25 to 24 hours. The product (IV) is generally purified by conventional procedures, e.g., extraction, distillation or crystallization, before use in the acylation reaction (2).

The acylation reaction (2) is conducted by conventional procedures in the presence of an organic amine such as a trialkyl amine or a pyridine compound. The reactants (IV) and (V) and the amine are generally contacted in substantially equimolar amounts in an inert organic solvent at a temperature of 0° to 100° C. Suitable inert organic solvents include ethyl acetate, methylene dichloride, dimethoxyethane, benzene, etc. The product is isolated and purified by conventional procedures such as extraction, distillation, chromatography, crystallization, etc.

The lactam compounds of the invention may be prepared by cyclizing a gamma-halo or delta-halo amide (VI) in the presence of a base and subsequently acylating the gamma-lactam or delta-lactam (VII) to give the 3-(N-acyl-N-arylamino)-gamma-lactam or delta-lactam product (I), as depicted in the following equations: ##STR4## wherein Ar, R, R¹, R², R³, R⁴, n and X have the same significance as previously defined.

The cyclization reaction (3) is conducted by treating the gamma-halo or delta-halo amide (VI) with substantially equimolar amounts of a strong inorganic base, e.g., alkali metal alkoxides such as sodium methoxide, potassium ethoxide, etc., and alkali metal hydrides such as sodium hydride. When an alkali metal alkoxide base is employed, the reaction is preferably conducted in an alkanol solvent such as methanol and ethanol. Whan an alkali metal hydride base is employed, the reaction is preferably conducted in a polar non-hydric oxygenated solvent such as dimethoxyethane. The lactam product (VII) is purified by conventional procedures such as extraction, distillation, chromatography or crystallization before use in the acylation reaction (4).

The acylation reaction (4) is conducted in the presence of an organic amine base by the same procedure disclosed above for reaction (2).

The gamma-halo or delta-halo amide reactant (VI) is suitably prepared by halogenating by conventional procedures, e.g., with phosphorus tribromide or thionyl chloride, the corresponding gamma-hydroxy or delta-hydroxy amide, i.e., the compound of formula (VIII): ##STR5##

The gamma-hydroxy or delta-hydroxy amide (VIII) in turn is prepared by reacting the 3-(N-arylamino)-gamma-lactone or delta-lactone (IV) with ammonia or an amine (H₂ NR⁴) in an inert solvent at a temperature of 25° to 100° C, and subsequently purifying the product by conventional procedures.

EXAMPLES

The preparation of the compounds of the invention by reactions (1) to (4) is illustrated by the following examples.

Example 1 -- Preparation of 3-(N-propionyl-N-3,4-dichlorophenylamino)-gamma-butyrolactone

A reaction flask was charged with 32.4 g (0.2 mol) of 3,4-dichloroaniline and 16.5 g (0.1 mol alpha-bromo-gamma-butyrolactone. The flask was evacuated to 20 mm of Hg and then slowly heated to 110°-145° C. The reaction pressure increased to 88 mm of Hg. After maintaining at about 23 mm of Hg and 120° C for 1 hour, the reaction mixture was cooled to give a solid mixture of 3,4-dichloroaniline hydrobromide salt and 3-(N-3,4-dichlorophenylamino)-gamma-butyrolactone. The mixture was treated with methylene chloride and filtered. The filtrate was evaporated to give the lactone product [(IV), Ar=3,4-dichlorphenyl, R, R² and R³ =H, n=1 and Y= O].

A solution of 5.9 g (0.024 mol) 3-(N-3,4-dichlorophenylamino)-gamma-butyrolactone, 2.1 g (0.026 mol) pyridine and 2.4 g (0.026 mol) propionyl chloride in 110 ml ethyl acetate was heated at 45° C. After 1/2-hour at 45° C, thin-layer chromatographic analysis showed substantial amounts of the lactone reactant. Another 2.1 g pyridine and 2.4 g propionyl chloride were added to the reaction mixture. The reaction mixture was then heated at reflux for 1/2 hour, cooled, washed with water, 10% aqueous sodium bicarbonate, water; dried over magnesium sulfate and evaporated to give an oil. The oil was chromatographed on a silica gel column. The product was eluted from the column as a colorless oil with 75:25 hexene/ether. The product crystallized from ether as a white solid. The melting point and elemental analysis on the product are tabulated in Table I, as compound No. 1.

Example 2 -- Preparation of 3-(N-3,4-dichlorobenzoyl-N-2,6-dimethylphenylamino-gamma-butyrolactone

A slurry of 12.2 g (0.1 mol) 2,6-dimethylaniline, 16.5 g (0.1 mol) alpha-bromo-gamma-butyrolactone, 10.6 g (0.1 mol) sodium carbonate and 150 ml dimethylformamide was heated at 125°-140° C for 21 hours. The reaction mixture was then diluted with water and extracted with benzene. The benzene extracts were washed with water, dried over magnesium sulfate and evaporated to give an oil. The oil was chromatographed on a silica gel column. 3-(N-2,6-dimethylphenylamino)-gamma-butyrolactone, m.p. 85°-87° C, was eluted from the column with 50:50 hexane/ether.

A solution of 6.2 g (0.03 mol) 3-(N-2,6-dimethylphenylamino)-gamma-butyrolactone, 6.9 g (0.033 mol) 3,4-dichlorobenzoyl chloride, 2.6 g (0.033 mol) pyridine and 150 ml ethyl acetate was stirred overnight at 25° C and then at 50°-75° C for 3 hours. After cooling, the reaction mixture was washed with water, diluted with methylene chloride, washed with water, 10% aqueous sodium bicarbonate, washed with water, dried over magnesium sulfate and evaporated to give a solid residue. The residue was crystallized from ethyl ether to give the product as a colorless solid. The melting point and elemental analysis for the product is tabulated in Table I, as compound No. 2.

Example 3 -- Preparation of 3-(N-chloroacetyl-N-2-methoxyphenylamino)-gamma-butyrolactone

A slurry of 12.3 g (0.1 mol) 2-methoxyaniline, 16.5 g (0.1 mol) alpha-bromo-gamma-butyrolactone, 10.6 g (0.1 mol) sodium carbonate and 150 ml dimethylformamide was stirred at 25° C for 16 hours and then at 90°-100° C for 6 hours. The reaction mixture was diluted with water and extracted with benzene. The benzene extracts were washed with water, dried over magnesium sulfate and evaporated to give an oil. The oil was chromatographed on a silica gel column. 3-(N-2-methoxyphenylamino)-gamma-butyrolactone was eluted from the column with 80:20 hexane/ether.

A 5.4 g (0.044 mol) sample of chloroacetyl chloride was added dropwise to a solution of 9 g (0.044 mol) 3-(N-2-methoxyphenylamino)-gamma-butyrolactone and 3.8 g (0.048 mol) pyridine in 150 ml ethyl acetate at 37°-46° C. After stirring at 46° C for 15 minutes, the reaction mixture was cooled and diluted with water. The organic layer was separated, washed with 10% aqueous sodium bicarbonate, washed with water, dried over magnesium sulfate and evaporated under reduced pressure to give the product, as a colorless solid. The melting point and elemental analysis for the product is tabulated in Table I, as compound No. 3.

Example 4 -- Preparation of 1-methyl-3-(N-chloroacetyl-N-2,6-dimethylphenylamino)-gamma-butyrolactam

A solution of 20.5 g (0.1 mol) 3-(N-2,6-dimethylphenyl)-gamma-butyrolactone, 4.7 g (0.15 mol) methylamine (40% solution in water) and 200 ml methanol was stirred at 25° C for 48 hours. The solvent was evaporated under reduced pressure to give an oil residue. The residue was dissolved in methylene chloride, washed with water, dried over magnesium sulfate and evaporated to give N-methyl-2-(N'-2,6-dimethylphenylamino)-4-hydroxybutyramide [(VIII), Ar=2,6-dimethylphenyl, R, R² and R³ =H, N--R⁴ =NCH₃, n=1].

A solution of 13.5 g (0.05 mol) phosphorus tribromide in 5 ml methylene chloride was added dropwise at 0° C (ice bath) to a solution of 23.6 g (0.1 mol) N-methyl-2-(N'-2,6-dimethylphenylamino)-4-hydroxybutyramide and 7.9 g (0.1 mol) pyridine in 200 ml methylene chloride. After the addition was completed, the reaction mixture was stirred at 25° C for 2 hours and at reflux for 1 hour. The reaction mixture was diluted with water. The organic layer was separated, washed with water, dried over magnesium sulfate and evaporated to give the crude N-methyl-2-(N'-2,6-dimethylphenylamino)-4-bromobutyramide [(VI), Ar=2,6-dimethylphenyl, R, R² and R³ =H, N--R⁴ =NCH₃ and n=1], as a glassy solid.

The crude bromo-amide was diluted with 150 ml ethanol and reacted with a solution of sodium ethoxide (prepared from 5.6 g of 43% NaH in mineral oil) in 100 ml ethanol at 25° C for about 16 hours. The reaction mixture was evaporated, dissolved in water and filtered. The aqueous filtrate was washed with petroleum ether, acidified to pH 1 with 10% hydrochloric acid, extracted with methylene chloride and evaporated to give 1-methyl-3-(N-2,6-dimethylphenylamino)-gamma-butyrolactam, as an oil.

Chloroacetyl chloride (1.8 g, 0.015 mol) was added dropwise to a stirred solution of 3 g (0.014 mol) 1-methyl-3-(N-2,6-dimethylphenylamino)-gamma-butyrolactam, 1.2 g (0.015 mol) pyridine and 50 ml ethyl acetate. The reaction mixture was stirred at 25° C for about 16 hours. The reaction mixture was then diluted with water and ether. The organic layer was separated, washed with saturated aqueous sodium bicarbonate, dried over magnesium sulfate and stripped to give an oil. The oil was chromatographed on a silica gel column. The product was eluted from the column with ether. The melting point and elemental analysis on the product is tabulated in Table I, as compound No. 4.

Example 5 -- Preparation of 1-allyl-3-(N-chloroacetyl-N-2,6-dimethylphenylamino)-gamma-butyrolactam

A solution of 20.5 g (0.1 mol) 3-(N-2,6-dimethylphenyl)-gamma-butyrolactone, 5.9 g (0.1 mol) allylamine and 200 ml methanol was stirred at 25° C for 16 hours and under reflux for 6.5 hours. An additional 2 g of allylamine was then added and heating under reflux continued for 4.5 hours. The solvent was then evaporated under reduced pressure to give an oil residue. The residue was chromatographed on silica gel (ether/petroleum ether elution) to give 21 g of N-allyl-2-(N'-2,6-dimethylphenylamino)-4-hydroxybutyramide [(VIII), Ar=2,6-dimethylphenyl, R, R² and R³ =H, N--R⁴ =NCH₂ CH=CH₂, n=1].

A sample of 8.7 g (0.073 mol) thionyl chloride was added dropwise at 0° C (ice bath) to a solution of 17.5 g (0.067 mol) N-allyl-2-(N'-2,6-dimethylphenylamino)-4-hydroxybutyramide in 250 ml methylene chloride. After the addition was completed, the reaction mixture was stirred at 25° C for 2 hours and at reflux until gas evolution ceased (about 12 hours). The reaction mixture was diluted with 200 ml water. The organic layer was separated, washed with water, dried over magnesium sulfate and evaporated to give the crude N-allyl-2-(N'-2,6-dimethylphenylamino)-4-chlorobutyramide [(VI), Ar=2,6-dimethylphenyl, R, R² and R³ =H, N--R⁴ = NCH₂ CH=CH₂ and n=1], as an oil.

The crude chloro-amide was diluted with 250 ml dimethoxyethane and reacted with 3.2 g of sodium hydride (50% in mineral oil). The reaction mixture was then stirred overnight at about 25° C, then filtered through Celite and washed with methylene chloride. The filtrate was evaporated and chromatographed on silica gel (ether/petroleum ether elution) to give 8.2 g of 1-allyl-3-(N-2,6-dimethylphenylamino)-gamma-butyrolactam, as an oil.

Chloroacetyl chloride (4.8 g, 0.042 mol) was added dropwise to a stirred solution of 9.4 g (0.039 mol) 1-allyl-3-(N-2,6-dimethylphenylamino-gamma-butyrolactam, 3.3 g (0.042 mol) pyridine and 100 ml ethyl acetate. The reaction mixture was stirred at 25° C for about 16 hours. The reaction mixture was then diluted with water. The organic layer was separated, washed with saturated aqueous sodium bicarbonate, dried over magnesium sulfate and stripped to give an oil. The oil was chromatographed on a silica gel column. The product (10.9 g was eluted from the column with ether. The melting point and elemental analysis on the product is tabulated in Table I, as compound No. 22.

Compound Nos. 6-21 and 23-25 of Table I were prepared by procedures similar to those of Examples 1-5. The structure of each compound tabulated in Table I was confirmed by nuclear magnetic resonance spectroscopy and/or infrared spectral analysis.

UTILITY

The compounds of the invention are useful for controlling fungi, particularly plant fungal infections. They act both as protectant fungicides, i.e., they prevent or protect against fungal infection, and as eradicant fungicides, i.e., they eliminate established infections. Furthermore, the compounds have been found to be highly active systemic fungicides, i.e., they are taken up by plants and move through cell membranes to prevent and/or eradicate fungal plant diseases.

The compounds of the invention are useful for controlling plant fungal infections such as Plasmopara viticola on grapevines, Botrytis cinerea on grapevines, Phytophthora infestans on tomatoes and potatoes, phytophthora parasitica, P.cinnamomi and P. palmivora on pineapples, Pseudoperonospora humili on hops, Peronospora tabacina on tobacco, Peronospora parasitics on cabbage and collard, Peronospora destructor on onions, and Phytophthora capsici on peppers.

However, some fungicidal compounds of the invention may be more fungicidally active than others against particular fungi. For example, the activity of the preferred compounds of formula (IA) is weak for many fungi, but highly specific and highly active for certain fungal diseases such as downy mildews, e.g., Plasmopara viticola (grapes) and Peronospora parasitics (cabbage and collard), and late blights, e.g., Phytophthora infestans (tomatoes).

The compounds of the invention are particularly useful fungicides because they cure established fungal infections. This permits economical use of the fungicides of the invention, because they need not be applied to plants unless fungal infection actually occurs. Thus, a preventive program of applying fungicides against potential fungal infection is not necessary.

Protectant or preventive fungicides and eradicant fungicides generally operate by completely different modes of action. For example, protectant or preventive fungicides generally prevent fungal infection by preventing sporulation and/or inoculation, whereas eradicant fungicides cure fungal diseases after the host is already infected. Therefore, it is highly surprising that the fungicides of the present invention act as both protectant and eradicant fungicides.

When used as fungicides, the compounds of the invention are applied in fungicidally effective amounts to fungi and/or their habitats, such as vegetative hosts and nonvegetative hosts, e.g., animal products. The amount used will, of course, depend on several factors such as the host, the type of fungus and the particular compound of the invention. As with most pesticidal compounds, the fungicides of the invention are not usually applied full strength, but are generally incorporated with conventional, biologically inert extenders or carriers normally employed for facilitating dispersion of active fungicidal compounds, recognizing that the formulation and mode of application may affect the activity of the fungicide. Thus, the fungicides of the invention may be formulated and applied as granules, as powdery dusts, as wettable powders, as emulsifiable concentrates, as solutions, or as any of several other known types of formulations, depending on the desired mode of application.

Wettable powders are in the form of finely divided particles which disperse readily in water or other dispersant. These compositions normally contain from 5-80% fungicide, and the rest inert material, which includes dispersing agents, emulsifying agents and wetting agents. The powder may be applied to the soil as a dry dust, or preferably as a suspension in water. Typical carriers include fuller's earth, kaolin clays, silicas, and other highly absorbent, wettable, inorganic diluents. Typical wetting, dispersing or emulsifying agents include, for example: the aryl and alkylaryl sulfonates and their sodium salts, alkylamide sulfonates, including fatty methyl taurides: alkylaryl polyether alcohols, sulfated higher alcohols and polyvinyl alcohols; polyethylene oxides, sulfonated animal and vegetable oils; sulfonated petroleum oils, fatty acid esters of polyhydric alcohols and the ethylene oxide addition products of such esters; and the addition products of long-chain mercaptans and ethylene oxide. Many other types of useful surface-active agents are available in commerce. The surface-active agent, when used, normally comprises from 1% to 15% by weight of the fungicidal composition.

Dusts are freely flowing admixtures of the active fungicide with finely divided solids such as talc, natural clays, kieselguhr, pyrophyllite, chalk, diatomaceous earths, calcium phosphates, calcium and magnesium carbonates, sulfur, lime, flours, and other organic and inorganic solids which act as dispersants and carriers for the toxicant. These finely divided solids have an average particle size of less than about 50 microns. A typical dust formulation useful herein contains 75% silica and 25% of the toxicant.

Useful liquid concentrates include the emulsifiable concentrates, which are homogeneous liquid or paste compositions which are readily dispersed in water or other dispersant, and may consist entirely of the fungicide with a liquid or solid emulsifying agent, or may also contain a liquid carrier such as xylene, heavy aromatic naphthas, isophorone, and other nonvolatile organic solvents. For application, these concentrates are dispersed in water or other liquid carrier, and are normally applied as a spray to the area to be treated.

Other useful formulations for fungicidal applications include simple solutions of the active fungicide in a dispersant in which it is completely soluble at the desired concentration, such as acetone, alkylated naphthalenes, xylene, or other organic solvents. Granular formultions, wherein the fungicide is carried on relatively coarse particles, are of particular utility for aerial distribution or for penetration of cover-crop canopy. Pressurized sprays, typically aerosols wherein the active ingredient is dispersed in finely divided form as a result of vaporization of a low-boiling dispersant solvent carrier, such as the Freons, may also be used. All of those techniques for formulating and applying fungicides are well known in the art.

The percentages by weight of the fungicide may vary according to the manner in which the composition is to be applied and the particular type of formulation, but in general comprise 0.5 to 95% of the toxicant by weight of the fungicidal composition.

The fungicidal compositions may be formulated and applied with other active ingredients, including other fungicides, insecticides, nematocides, bactericides, plant growth regulators, fertilizers, etc.

Example 6 -- Tomato Late Blight

Compounds of the invention were tested for the control of the Tomato Late Blight organism Phytophthora infestans. Five- to six-week-old tomato (cultivar Bonny Best) seedlings were used. The tomato plants were sprayed with a 250-ppm solution of the test compound in acetone, water and a small amount of a non-ionic emulsifer. The sprayed plants were then inoculated one day later with the organism, placed in an environmental chamber and incubated at 66°-68° F and 100% relative humidity for at least 16 hours. Following the incubation, the plants were maintained in a greenhouse at 60-80% relative humidity for approximately 7 days. The percent disease control provided by a given test compound was based on the percent disease reduction relative to untreated check plants. The compounds found to be effective at the test concentration and the results are tabulated in Table II.

Example 7 -- Tomato Early Blight

Compounds of the invention were tested for the control of the Tomato Early Blight organism, Alternaria solani. Tomato (cultivar Bonny Best) seedlings of 6 to 7 weeks old were used. The tomato plants were sprayed with a 250-ppm solution of the test compound in an acetone-and-water solution containing a small amount of a non-ionic emuslfier. The sprayed plants were inoculated one day later with the organism, placed in an environmental chamber, incubated at 66°-68° F in 100% relative humidity for 2 days, and then maintained in a greenhouse at 66-68° F for 5 days. Percent disease control was based on the percent disease development on untreated check plants. The compounds found to be effective at the test concentrations and the results are tabulated in Table II.

Example 8 -- Celery Late Blight

Compounds of the invention were tested for the control of Celery Late Blight using celery (cultivar Utah) plants 11 weeks old. The Celery Late Blight organism was Septoria apii. The celery plants were sprayed with solutions of the candidate toxicant mixed with acetone, water and a nonionic emulsifer. The plants were then inoculated with the organism and placed in an environmental chamber and incubated at 66°-68° F in 100% relative humidity for an extended period of time (approximately 24 hours). Following the incubation, the plants were maintained at a 60-80% relative humidity in a greenhouse for approximately 14 days. The percent disease control provided by a given candidate toxicant is based on the percent disease reduction relative to untreated check plants. The compounds found to be effective at the test concentrations and the results are tabulated in Table II.

Example 9 -- Botrytis cinerea control

Compounds of the invention were tested for Botyrtis cinerea control using detached, well-developed primary leaves of a 4-6 week old horsebean plant. The leaves were dipped into a 40-ppm solution of the test compound in acetone and water containing a small amount of a nonionic emulsifier, then taken out and placed in a petri plate lined with two pieces of filter paper. The leaves were allowed to dry while the filter paper was kept moist by adding water as required. The treated leaves were then inoculated with the spores of Botrytis cinerea fungus grown on potato dextrose agar plates. The plate was covered after inoculation and kept at 23.5° C. The filter-paper lining of the plate was kept saturated with water throughout the test. The rate of disease incidence was determined in 3 to 5 days, when the disease symptoms were fully evident on non-treated check leaves. The percentage disease control provided by the test compound was calculated as the percentage disease reduction based on the nontreated check leaves. The compounds found to be effective at the test concentration and the results are tabulated in Table II.

Example 10 -- Powdery Mildew

The powdery mildew test was made using bean seedlings (cultivar Bountiful) with well-developed primary leaves. The pathogen was Erysiphe polygoni. The bean seedlings were sprayed with a 250-ppm solution of the test compound in an acetone-water mixture containing a nonionic emulsifier. The treated plants were inoculated one day after spray application of the test compound with the pathogen. The plants were then maintained in a greenhouse at a 60-80% relative humidity and at a temperature of 68°-70° F. The rate of infection on the leaves was made after about 10 days. The percent disease control provided by a given test compound was based on the disease reduction relative to untreated check plants. The compounds found to be effective at the test concentrations and the results are tabulated in Table II. The compounds found to be effective at the test concentrations and the results are tabulated in Table II.

Example 11 -- Preventative Grape Downy Mildew Control

Compounds of the invention were tested for the control of the grape downy mildew organism Plasmopara viticola. Detached leaves between 70 and 80 mm in diameter of 7-week-old Vitis vinifera cultivar Emperor grape seedlings were used as hosts. The leaves were sprayed with a 500-ppm solution of the test compound in acetone, water and a small amount of a nonionic emulsifer. The sprayed leaves were dried, inoculated with the organism, placed in an environment chamber and incubated at 18°-22° C and about 100% relative humidity. Seven to 9 days after inoculation, the amount of disease control was determined. The percent disease control provided by a given test compound was based on the percent disease reduction relative to untreated check plants. The test compounds and the results are tabulated in Table III.

Example 12 -- Eradicant Grape Downy Mildew Control

Compounds of the invention were tested for the eradicant control of the grape downy mildew organism Plasmopara viticola. Detached leaves of between 70 and 80 mm diameter of 7-week-old Vitis vinifera cultivar Emperor grape seedlings were used as hosts. The leaves were inoculated with the organism and placed in an environment chamber and incubated at 18°-22° C and at about 100% relative humidity for 1 to 2 days. The leaves were then sprayed with a 500-ppm solution of the test compound in acetone, water and a small amount of a nonionic emulsifier. The sprayed leaves were then maintained at 18°-22° C and at about 100% relative humidity. Seven to nine days after inoculation, the amount of disease control was determined. The percent disease control provided by a given test compound was based on the percent disease reduction relative to nontreated check plants. The time of treatment with the test compound (days after inoculation) and the results are tabulated in Table IV.

Example 13 -- Eradicant Tomato Late Blight Control

Several compounds of the invention were tested for the eradicant control of the Tomato Late Blight organism Phytophthora infestans. Five- to six-week-old tomato (cutilvar Bonny Best) plants were used. The tomato plants were inoculated with the organism, placed in an environmental chamber and incubated at 18°-22° C and 100% relative humidity for 2 days. The plants were then sprayed with a solution of the test compound in acetone, water and a small amount of a nonionic emulsifier. The sprayed plants were allowed to dry and then were maintained in a greenhouse at 18°-22° C and at 95-100% relative humidity. Seven days after inoculation the plants were observed for fungal infections. The amount of disease control provided by a given test compound was based on the amount of disease reduction relative to untreated check plants. The results in terms of ED₅₀ (ppm of applied spray for 50% control) and ED₉₀ (ppm of applied spray for 90% control) values are tabulated in Table V.

Example 14 - Systemic Soil Drench

Compound Nos. 8 and 14 were tested to determine their systemic activity in soil drench applications against the Tomato Late Blight organism Phytophthora infestans.

Five- to six-week-old tomato (cultivar Bonny Best) plants were used as host. Pots containing the plants were treated with the test compound at various test concentrations. The plants were then placed in a greenhouse, maintained at 18°-22° C and about 70% relative humidity. Three days after treatment, the plants were inoculated with the organism. Fungal infection readings were made when disease symptoms were evident on the nontreated control plants (approximately 7-9 days after inoculation). In a similar manner, the plants were inoculated 10 and 20 days after treatment and the amount of fungal infection determined. The percent of disease control provided by a given test compound was based on the percent disease reduction relative to the nontreated check plants. The test compound, time of inoculation, the test concentration and the percent disease control are tabulated in Table VI.

Example 15 -- Preventive Grape Downy Mildew Control

A test was conducted to compare the effectiveness of 3-(N-chloroacetyl-N-2,6-dimethylphenylamino)-gamma-butyrolactone and two commercial fungicides for the control of grape downy mildew Plasmopara vitocola). The commercial fungicides used were Folpet [N-(trichloromethylthio)phthalimide] and Captafol [cis-N-(1,1,2,2-tetrachloroethylthio)-4-cyclohexene-1,2-dicarboximide]. The test was conducted as follows:

Detached leaves of 3-month-old Cabernet Sauvignon grape plants were used as hosts. Four leaves were used in each test. The leaves were sprayed with a solution of the test compound in a 1% acetone/99% water solution containing 40 ppm of a nonionic surfactant. The sprayed leaves were dried and inoculated with 25 droplets of a sporangial suspension of the organism (400,000 conidia/milliliter water). After inoculation, the leaves were kept in a high-humidity chamber. After 10 days, the amount of disease control was determined. The percent disease control provided by the test compound was based on the percent disease reduction relative to untreated check leaves. The test compound, the test concentration and the percent control are tabulated in Table VII.

Example 16 -- Fermentation Test

An in-vitro test was carried out to determine the influence of 3-(N-chloroacetyl-N-2,6-dimethylphenylamino)-gamma-butyrolactone (Compound No. 8) on yeasts responsible for the alcoholic fermentation of grapes. The test was conducted as follows:

Erlenmeyer flasks (500 cc) were filled with 200 cc of grape juice (density 1.07 gm/cc) extracted from bunches of Madeleine Angevine grapes. The test compound was added to the grape juice and the extent of fermentation determined by measuring the cumulated loss of weight due to carbon dioxide escape. For comparison, the test was conducted with an untreated check and the commercial fungicide N-(trichloromethylthio)-phthalimide (Folpet). The concentration of test compound and the results for the first 8 days of fermentation are tabulated in Table VIII.

Example 17 -- Eradicant Downy Mildew Control

3-(N-chloroacetyl-N-2,6-dimethylphenylamino)-gammabutyrolactone (Compound No. 8) and several commercial fungicides were tested for the eradicant control of downy mildew (Plasmopara viticola) on grape leaves. The commercial fungicides employed were:

Captafol -- cis-N-(1,1,2,2-tetrachloroethylthio)-4-cyclohexene-1,2-dicarboximide

Fentinacetate -- triphenyltin acetate

Chlorothalonil -- 2,4,5,6-tetrachloroisophthalonitrile

Cupric sulfate

Detached leaves of Carignane and Emperor grape plants were used as hosts. The leaves were inoculated with the organism and placed in an environment chamber and incubated at 18°-22° and at about 100% relative humidity for 1 to 3 days (1 to 2 days for Emperor leaves, 3 days for Carignane leaves). The leaves were then sprayed with a solution of the test compound in acetone, water, and a small amount of nonionic emulsifier. The sprayed leaves were then maintained at 18°-22° C and at about 100% relative humidity. Eight to nine days after inoculation, the amount of disease control was determined. The percent disease control provided by a given test compound was based on the percent disease reduction relative to nontreated check leaves. The test compound, the grape leaf variety, the time of treatment with the test compound (days after inoculation) and the results in terms of ED₅₀ (ppm of applied spray for 50% control) and ED₉₀ (ppm of applied spray for 90% control) are tabulated in Table IX.

                                      TABLE I                                      __________________________________________________________________________      ##STR6##                                                                                                                 Halogen                                                                 Melting                                                                               Analysis                            No.                                                                               Ar          Y        R.sup.1 R   Point, ° C                                                                     Calc.                                                                              Found                           __________________________________________________________________________      1 3,4-dichlorophenyl                                                                         O        CH.sub.2 CH.sub.3                                                                      H   112-114                                                                               23.5                                                                               23.1                             2 2,6-dimethylphenyl                                                                         O        3,4-diCl-φ                                                                         H   151-160                                                                               18.8                                                                               22.5                             3 2-methoxyphenyl                                                                            O        CH.sub.2 Cl                                                                            H   123-124                                                                               12.5                                                                               12.1                             4 2,6-dimethylphenyl                                                                         NCH.sub.3                                                                               CH.sub.2 Cl                                                                            H   121-122                                                                               12.0                                                                               12.0                             5 phenyl      O        CH.sub.2 Cl                                                                            H   91-93  14.0                                                                               14.1                             6 2,6-diethylphenyl                                                                          O        CH.sub.2 Cl                                                                            H   104-105                                                                               11.5                                                                               11.4                             7 2-isopropyphenyl                                                                           O        CH.sub.2 Cl                                                                            H   152-154                                                                               12.0                                                                               11.3                             8 2,6-dimethylphenyl                                                                         O        CH.sub.2 Cl                                                                            H   141-143                                                                               12.6                                                                               12.8                             9 2-ethylphenyl                                                                              O        CH.sub.2 Cl                                                                            H   108-109                                                                               12.6                                                                               12.4                            10 2,6-dichlorophenyl                                                                         O         CH.sub.2 Cl                                                                           H   172-174                                                                               33.0                                                                               31.7                            11 3,4-dichlorophenyl                                                                         O        CH.sub.2 Cl                                                                            H   48-50  33.0                                                                               30.6                            12 3,5-dichlorophenyl                                                                         O        CH.sub.2 Cl                                                                            H   143-144                                                                               33.0                                                                               31.4                            13 2,6-diethylphenyl                                                                          O        CH.sub.2 Cl                                                                            CH.sub.3                                                                           36-37  11.0                                                                               11.0                            14 2,6-dimethylphenyl                                                                         O        CH.sub.2 Cl                                                                            CH.sub.3                                                                           34-35  12.0                                                                               12.2                            15 2-methyl-6-ethylphenyl                                                                     O        CH.sub.2 Cl                                                                            H   119-120                                                                               12.0                                                                               12.1                            16 2-methyl-6-ethylphenyl                                                                     O        CH.sub.2 Cl                                                                            CH.sub.3                                                                           92-94  11.5                                                                               11.5                            17 2,6-dimethylphenyl                                                                         O        CH.sub.2 Br                                                                            H   116-117                                                                               24.5                                                                               25.1                            18 2,6-dimethoxyphenyl                                                                        O        CH.sub.2 Cl                                                                            H   148-150                                                                               11.3                                                                               11.3                            19 2,6-dimethylphenyl                                                                         O        CH.sub.2 CH.sub.2 Cl                                                                   H   108-109                                                                               12.0                                                                               11.8                            20 2,6-dimethylphenyl                                                                         NCH(CH.sub.3).sub.2                                                                     CH.sub.2 Cl                                                                            H   67-69  11.0                                                                               10.8                            21 2,6-dimethylphenyl                                                                         O        CClCCl.sub.2                                                                           H   129-130                                                                               29.3                                                                               28.7                            22 2,6-dimethylphenyl                                                                         NCH.sub.2 CHCH.sub.2                                                                    CH.sub.2 Cl                                                                            H   oil    11.1                                                                               12.1                            23 2,6-dimethylphenyl                                                                         NH       CH.sub.2 Cl                                                                            H   152-154                                                                               12.6                                                                               12.5                            24 2,6-dimethylphenyl                                                                         N(3-CH.sub.3 -4-Cl)φ                                                                CH.sub.2 Cl                                                                            H   137-140                                                                               17.5                                                                               17.1                            25 2,6-dimethylphenyl                                                                         NCH.sub.3                                                                               4-Cl-φ                                                                             H   169-174                                                                               9.93                                                                               10.3                            __________________________________________________________________________      φ= phenyl                                                            

                                      TABLE II                                     __________________________________________________________________________     % Control                                                                      Compound                                                                             Tomato  Tomato  Celery  Botrytis                                                                            Bean                                        No.   Late Blight                                                                            Early Blight                                                                           Late Blight                                                                            cinerea                                                                             Powdery Mildew                              __________________________________________________________________________      1    --      --      73      --   --                                           2    --      --      27      --   --                                           3    23      98      21      --   44                                           4    13      92      --      --   --                                           5    11      63      21      17   --                                           6    39      --      18      56   --                                           7    --      56      39      --   --                                           8    100     44      21      87   --                                           9    35      21      21      --   --                                          10    --      27      33      --   14                                          11    --      81      60      --   --                                          12    --      --      --      --   --                                          13    21      --      --      --   --                                          14    100     --      --      --   64                                          15    95      --      23      --   --                                          16    --      --      --      17   --                                          17    --      --      27      --   --                                          18    --      --      --      42    8                                          19    --      --      23      33   --                                          20    --      11      --      --   69                                          21    44      --      23      --   --                                          22    --      --      23      --   23                                          23    --      --      35      --   --                                          24    --      63      18      --   --                                          25    --      23      --      --   --                                          __________________________________________________________________________

                  TABLE III                                                        ______________________________________                                                         % Preventative                                                 Compound        Downy Mildew                                                   No.             Control                                                        ______________________________________                                          1              31                                                              2               6                                                              3              15                                                              4              62                                                              5              91                                                              6              93                                                              7              44                                                              8              85                                                              9              93                                                             11              13                                                             12              47                                                             13              87                                                             14              53                                                             15              85                                                             16              94                                                             17              13                                                             19              31                                                             20              98                                                             21              69                                                             22              15                                                             23              44                                                             24              92                                                             25              94                                                             ______________________________________                                    

                  TABLE IV                                                         ______________________________________                                                        % Eradication of                                                Compound       Downy Mildew                                                    No.            1 day        2 days                                             ______________________________________                                          1             94           --                                                  2             82           --                                                  3             --           45                                                  5             --           29                                                  7             --           78                                                  8             --           100                                                 9             --           73                                                 11             95           --                                                 12             --           91                                                 13             --           45                                                 14             --           93                                                 15             92           --                                                 16             54           --                                                 17             87           --                                                 18             89           --                                                 19             68           --                                                 20             --           29                                                 21             --           39                                                 23             54           --                                                 24             68           --                                                 25             --           29                                                 ______________________________________                                    

                  TABLE V                                                          ______________________________________                                                        Eradication of                                                  Compound       Tomato Late Blight                                              No.            ED.sub.50 /ED.sub.90                                            ______________________________________                                         1              14/29                                                           3               10/100                                                         5              14/90                                                           7              22/45                                                           8              0.3/2.5                                                         9               6/160                                                          11              2/100                                                          ______________________________________                                    

                  TABLE VI                                                         ______________________________________                                                  Test                                                                  Test     Concentration                                                                               % Control                                                Compound (lbs/acre)   2 days   10 days                                                                               20 days                                  ______________________________________                                         No. 8    8.9          100      100    99                                                3.6          100      99     95                                                1.4          100      97     95                                       No. 14   8.9          100      100    99                                                3.6          100      99     97                                                1.4           99      97     92                                       ______________________________________                                    

                  TABLE VII                                                        ______________________________________                                         Test     Percent Control                                                       Compound 40 ppm      16 ppm      6.4 ppm                                       ______________________________________                                         No. 8    100         100         100                                           Folpet   97.7        98.8        80.1                                          Captafol 96.5        98.8        95.3                                          ______________________________________                                    

                  TABLE VIII                                                       ______________________________________                                                        Cumulated loss of weight (in grams)                             Product                                                                               Conc.   due to CO.sub.2 escape after                                    added  ppm     1 day   2 days                                                                               3 days                                                                              4 days                                                                              7 days                                                                               8 days                            ______________________________________                                         No. 8  1       0.9     5.0   10.5 11.3 14.2  14.5                                     2       0.8     5.2   10.4 11.1 13.4  13.7                                     4       1.0     5.2   10.4 11.1 13.1  13.3                                     8       1.0     5.4   11.0 11.8 14.5  15.2                              Folpet 1       0.4     0.5    2.8  3.6  8.9  10.1                                     2       0.2     0.4    1.3  1.8  4.7   5.6                                     4       0.4     0.4    0.7  0.8  2.1   3.1                                     8       0.3     0.4    0.7  1.2  1.5                                    None   --      0.9     5.4   11.1 11.6 14.2  14.5                              ______________________________________                                    

                  TABLE IX                                                         ______________________________________                                                   Eradication ED.sub.50 /ED.sub.90                                     Test        Emperor leaves  Carignane leaves                                   Compound    1 day     2 days    3 days                                         ______________________________________                                         No. 8       9.3/58     27/99    20.7/113                                       Captafol     55/145    64/168   206/670                                        Fentinacetate                                                                               47/171    88/219   254/562                                        Chlorothalonil                                                                             128/293   410/1000+ 313/992                                        Cupric sulfate                                                                             118/289   204/445   380/610                                        ______________________________________                                     

What is claimed is:
 1. A method for the control of fungi which comprises contacting said fungi or their habitats with a fungicidally effective amount of a compound of the formula ##STR7## wherein Ar is phenyl or phenyl substituted with 1 to 3 of the same or different substituents selected from trifluoromethyl, trichloromethyl, fluoro, chloro, bromo, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms or nitro; R is hydrogen or alkyl of 1 to 6 carbon atoms; R¹ is alkyl of 1 to 6 carbon atoms, haloalkyl of 1 to 3 carbon atoms and 1 to 5 of the same or different halogen selected from fluoro, chloro or bromo, halovinyl of from 1 to 3 of the same or different halogens selected from fluoro, chloro or bromo, phenyl, or phenyl substituted with 1 to 3 of the same or different substituents selected from trifluoromethyl, trichloromethyl, fluoro, chloro, bromo, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms or nitro; R² is hydrogen or alkyl of 1 to 6 carbon atoms; R³ is hydrogen or alkyl of 1 to 6 carbon atoms; n is 1 or 2; and Y is O.
 2. The method of claim 1 wherein R¹ is alkyl.
 3. The method of claim 1 wherein R, R² and R³ are hydrogen, and R¹ is haloalkyl of 1 to 3 carbon atoms and of 1 to 2 chloro or bromo.
 4. The method of claim 1 wherein R, R² and R³ are hydrogen, R¹ is chloromethyl or bromomethyl, Ar is 2,6-dialkylphenyl, and n is
 1. 5. The method of claim 1 wherein R, R² and R³ are hydrogen, R¹ is chloromethyl, Ar is 2,6-dimethylphenyl, and n is
 1. 6. The method of claim 1 wherein R, R² and R³ are hydrogen, and R¹ is phenyl or phenyl substituted with 1 to 2 of the same or different substituents selected from fluoro, chloro, bromo or alkyl of 1 to 6 carbon atoms.
 7. A method for preventing the growth of downy mildew fungi in plants which comprises applying to plant hosts of said fungi a fungicidally effective amount of a compound of the formula defined in claim
 1. 8. A method for eradicating downy mildew fungal infection on plants which comprises applying to plants having downy mildew fungal infection a fungicidally effective amount of a compound of the formula defined in claim
 1. 9. A fungicidal composition comprising a biologically inert carrier and a fungicially effective amount of a compound of the formula defined in claim
 1. 10. The composition of claim 9 wherein R¹ is alkyl.
 11. The composition of claim 9 wherein R, R² and R³ are hydrogen, and R¹ is haloalkyl of 1 to 3 carbon atoms and of 1 to 2 chloro or bromo.
 12. The composition of claim 9 wherein R, R² and R³ are hydrogen, R¹ is chloromethyl or bromomethyl, Ar is 2,6-dialkylphenyl, and n is
 1. 13. The composition of claim 9 wherein R, R² and R³ are hydrogen, R¹ is chloromethyl, Ar is 2,6-dimethylphenyl, and n is
 1. 14. The composition of claim 9 wherein R, R² and R³ are hydrogen, and R¹ is phenyl or phenyl substituted with 1 to 2 of the same or different substituents selected from fluoro, chloro, bromo or alkyl of 1 to 6 carbon atoms.
 15. A compound of the formula ##STR8## wherein Ar is phenyl or phenyl substituted with 1 to 3 of the same or different substituents selected from fluoro, chloro, bromo, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms or nitro; R¹ is halovinyl of 1 to 3 of the same or different halogens selected from fluoro, chloro or bromo; R² is hydrogen or alkyl of 1 to 6 carbon atoms; R³ is hydrogen or alkyl of 1 to 6 carbon atoms; and n is 1 or
 2. 16. The compound of claim 15 wherein R, R² and R³ are hydrogen.
 17. The compound of claim 15 wherein R, R² and R³ are hydrogen, Ar is 2,6-dialkylphenyl, and n is
 1. 18. The compound of claim 15 wherein R, R² and R³ are hydrogen, R¹ is trichlorovinyl, Ar is 2,6-dimethylphenyl, and n is
 1. 19. A method for preventing the growth of downy mildew fungi on grapevines which comprises applying to the grapevines a fungicidally effective amount of a compound of the formula defined in claim
 1. 20. The method of claim 19 wherein the compound is defined by the formula ##STR9## wherein R¹ is halomethyl of 1 to 3 chloro or bromo atoms, R² is hydrogen or alkyl of 1 to 3 carbon atoms, R⁵ is hydrogen or alkyl of 1 to 3 carbon atoms and R⁶ is alkyl of 1 to 3 atoms.
 21. The method of claim 20 wherein R¹ is chloromethyl, R² is hydrogen, R⁵ is methyl or ethyl, and R⁶ is methyl or ethyl.
 22. The method of claim 21 wherein R¹ is chloromethyl, R² is hydrogen and R⁵ and R⁶ are methyl.
 23. The method of claim 21 wherein R¹ is chloromethyl, R² is hydrogen, R⁵ is methyl and R⁶ is ethyl.
 24. The method of claim 21 wherein R¹ is chloromethyl, R² is hydrogen, and R⁵ and R⁶ are ethyl.
 25. A method for eradicating downy mildew infection on grapevines which comprises applying to grapevines having downy mildew infection a fungicidally effective amount of a compound of the formula defined in claim
 1. 26. The method of claim 25 wherein the compound is defined by the formula ##STR10## wherein R¹ is halomethyl of 1 to 3 chloro or bromo atoms, R² is hydrogen or alkyl of 1 to 3 carbon atoms, R⁵ is hydrogen or alkyl of 1 to 3 carbon atoms and R⁶ is alkyl of 1 to 3 carbon atoms.
 27. The method of claim 26 wherein R¹ is chloromethyl, R² is hydrogen or methyl, R⁵ is methyl or ethyl, and R⁶ is methyl or ethyl.
 28. The method of claim 27 wherein R¹ is chloromethyl, R² is hydrogen, and R⁵ and R⁶ are ethyl.
 29. The method of claim 27 wherein R¹ is chloromethyl, R² is hydrogen and R⁵ and R⁶ are methyl.
 30. The method of claim 27 wherein R¹ is chloromethyl, R² is hydrogen, R⁵ is methyl and R⁶ is ethyl.
 31. A method for controlling downy mildew on grapevines which produce grapes used for fermentation which comprises applying to grapevines a fungicidally effective amount of a compound of the formula defined in claim
 1. 32. The method of claim 31 wherein the compound is defined by the formula ##STR11## wherein R¹ is halomethyl of 1 to 3 chloro or bromo atoms, R² is hydrogen or alkyl of 1 to 3 carbon atoms, R⁵ is hydrogen or alkyl of 1 to 3 carbon atoms and R⁶ is alkyl of 1 to 3 carbon atoms.
 33. The method of claim 32 wherein R¹ is chloromethyl, R² is hydrogen, R⁵ is methyl or ethyl, and R⁶ is methyl or ethyl.
 34. The method of claim 33 wherein R¹ is chloromethyl, R² is hydrogen and R⁵ and R⁶ are methyl.
 35. The method of claim 33 wherein R¹ is chloromethyl, R² is hydrogen, R⁵ is methyl and R⁶ is ethyl.
 36. The method of claim 33 wherein R¹ is chloromethyl, R² is hydrogen and R⁵ and R⁶ are ethyl. 